Disease and Risk Profile · Maize · Ghana Agribusiness Playbook

Disease and Risk · Pillar 03

Most guides treat pests and disease as problems to survive. This one treats them as markets. Every threat that costs a maize farmer money is, for someone else, a product to sell or a service to provide: the armyworm creates a market for scouting and biopesticides, the mould creates a market for testing and safe storage, and the drought creates a market for tolerant seed and insurance. The losses are real and large, but they are also the clearest map of where a new business can add value. This pillar reads the big risks that way, and points to the opening inside each.

Fall armyworm damage on a maize leaf and cob in the field

Every threat is a market

The size of each loss is also the clearest map of where a new business can add value.

22-67%

fall armyworm can take of a field's yield

~84%

cut in the most toxic aflatoxin (AFB1) from Aflasafe GH02 in one Ghanaian trial

~15%

of the maize crop is lost after harvest

The pillar keeps to the threats and their management. The warehouse-receipt mechanism that lets a farmer store safely and borrow against the grain sits in the value-chain and business-intelligence pillars, and is only touched here as a loss to be avoided, so nothing is repeated.

Figure 5 Aflatoxin: a health threat, a market barrier, and a business

What this shows

Contaminated grain is rejected by feed mills and institutional buyers, so aflatoxin is a barrier to the best-paying buyers. In one Ghanaian trial, Aflasafe GH02 cut the most toxic form (AFB1) by about 84 percent, and hermetic bags kept levels lower still in storage, which helps make clean grain a premium product.

15%+

of maize samples exceed the safety limit nationally

445 ppb

the highest aflatoxin reading found on open markets

🌽 Fall armyworm: the pest that changed maize farming 🌽

Since it arrived in 2016, fall armyworm has been the biggest single pest threat to Ghanaian maize. Early estimates put its toll at between about 22 and 67 percent of yield across West Africa, with the worst damage in dry-season crops, although a Ghana panel study found that by 2020, as farmers adopted better control, its effect on yields was no longer statistically significant¹. National losses were put at about 132,450 tonnes in 2016, 180,000 in 2017 and 36,000 in 2018 as farmers learned to fight it². The important business point is not the loss itself but how badly it is being fought. Trials in northern Ghana show that the products that work are already known: neem (3 percent azadirachtin), Bacillus thuringiensis (Bt) formulations, and a granulosis-virus-plus-Bt mix all matched chemical sprays on cob damage and yield in on-station and on-farm trials in the 2020 rainy season³. Farmers who adopt recommended practices such as early planting and prescribed pesticides also achieve better farm performance⁴. Much of the loss comes from how and when products are used.

Put the numbers together and the waste is stark. A smallholder who sprays six or more times can spend over GH¢1,000 on chemicals and still lose more than GH¢4,000 of crop, when scouting and spraying only when pest thresholds are reached would cut both the cost and the loss⁵. That gap between what farmers spend and what works is the opening.

A field agent scouting a maize plant for fall armyworm larvae

How and when you spray

The products that work are already known, so the opening is a scouting and timed-spray service.

Mould-contaminated maize grain being sorted from clean grain

Clean grain is a premium product

Biopesticides matched chemical sprays on cob damage and yield in northern trials.

Maize grain sealed in an airtight PICS hermetic storage bag

US$2 a bag

Hermetic bags are cheap, well-tested products with a large market.

GH¢1,000+

spent on chemicals by a smallholder who sprays six or more times

2016

the year armyworm arrived and changed maize farming

🌽 Aflatoxin: a health threat that is also a market barrier 🌽

Aflatoxin is a poison made by a mould that grows on maize in the field and in poor storage, and it is one of Ghana’s most serious and commercially damaging maize problems. In one national survey about 15 percent of maize samples exceeded the safety limit⁶, while a survey of maize on open markets found roughly half of samples over the limit, some testing as high as 445 parts per billion⁷. A 2024 sampling of a poultry-feed chain found nearly all of it contaminated⁸. Beyond the grain it downgrades and spoils, aflatoxin carries a real health cost: Ghana has one of Africa’s highest liver-cancer rates, at about 16 cases per 100,000 people a year, to which dietary aflatoxin contributes⁹. Read commercially, aflatoxin is the reason a farmer cannot reach the buyers who pay best. Larger feed mills and processors test for it and can reject grain that fails, and export buyers would do the same if the export ban were lifted. That makes clean grain a premium product, not just a safe one. The tools exist: the biocontrol product Aflasafe GH02, applied in the field, cut the main aflatoxin toxin (AFB1) by about 84 percent in a Ghanaian trial, although from levels that were already low, and earlier African studies report reductions in total aflatoxin of 80 to 99 percent, and it works best when paired with fast drying and airtight storage¹⁰. The business is in delivering that combination and certifying the result. The maximum level allowed in maize is commonly given as 15 parts per billion, but published sources cite between 10 and 20, so the current Ghana Standards Authority figure should be confirmed before it is used in a contract.

~half

of open-market maize samples were over the aflatoxin limit

~84%

reduction in the main toxin (AFB1) from Aflasafe GH02 in one Ghanaian trial

Maize grain being tested for aflatoxin at a point of aggregation

Testing is a service business

Aflatoxin is the reason a farmer cannot reach the buyers who pay best, which makes clean grain a premium product.

🌽 Storage loss: the fight after harvest 🌽

About 15 percent of Ghana’s maize is lost after harvest, and where storage is poor, figures of around 30 percent are commonly cited¹¹. In 2021 the national loss was put at about 276,569 tonnes, worth roughly US$134 million, which is close to GH¢1.5 billion at about GH¢11.2 to the US dollar¹². The fix is cheap and well tested: airtight hermetic bags such as PICS cost about US$2 a bag at earlier prices (confirm the current cedi price with local dealers) and cut grain weight loss to about 0.2 percent after six months, against almost 30 percent in an ordinary polypropylene sack, in a Ghanaian trial¹³. Yet in one Ashanti Region study, fewer than one in five farmers used them¹⁴. The payoff for those who do adopt is not small: a 2024 study found that taking up hermetic storage raised farm income by about 90 percent and cut post-harvest losses by 14 to 19 percent, while narrowing the income gap between richer and poorer farming households¹⁴. That is a strong return case, and it is a ready-made pitch for anyone selling storage.

+90%

farm income lift from taking up hermetic storage

1 in 5

fewer than this share of farmers used hermetic bags in one Ashanti study

Stacks of airtight hermetic maize storage bags in a rural warehouse

A strong return case

PICS bags cost about US$2 and cut weight loss to about 0.2 percent after six months, against almost 30 percent in an ordinary sack.

Figure 6 Where maize value leaks, and why storage must be cheap

What this shows

A farmer loses about 15 percent of the crop to spoilage, and farmers who sell cheap at harvest and buy dear later lose a further share of its value to the price swing. Storage and warehouse receipts recover both. This is the clearest business case in the whole crop, and it is developed in full in the value-chain and business-intelligence pillars.

~15%

of the crop lost to spoilage after harvest

~33%

average wholesale price rise from October to July

~28%

of the grain's value that storage and loan interest can cost over nine months

🌽 The second leak: timing 🌽

There is a second leak, in timing. Farmers who sell the moment they harvest, when prices are lowest, often buy grain back in the lean season at a higher price. In Ghana, wholesale maize prices rise on average about 33 percent between October and July, but storage and loan interest can cost about 28 percent of the grain’s value over nine months, so holding grain only pays when storage is safe and cheap and the finance behind it is affordable¹¹. Anything that lets a farmer store safely and sell later, hermetic bags, a community warehouse, or a warehouse receipt that unlocks a loan against stored grain, captures that value. The warehouse-receipt mechanism itself sits in the value-chain and business-intelligence pillars.

🌽 Drought and the shrinking rains: the master risk 🌽

More than 80 percent of Ghana’s maize is rain-fed, so weather is the risk that overrides all others. The 2024 drought cut national output by about 28 percent and hit some 871,000 hectares and 436,000 farmers¹⁵, and it triggered emergency imports and a tightening of the grain export ban first imposed in 2022, which shaped the 2026 market¹⁶. Yields fall as temperatures climb, and models project maize yields declining further as the climate warms; one crop-model study at Ejura projected cuts of about 14 to 20 percent for 2030 to 2050¹⁷, and climate already explains a large share of yield swings in dry years¹⁸. This is why the drought-tolerant varieties in Pillar 1 matter commercially, and why weather-index insurance and small-scale irrigation are growing markets. The Ghana Agricultural Insurance Pool has offered drought-index cover for maize since 2011, though take-up is still small¹⁹.

Two lower-profile threats are worth watching. Maize streak virus, spread by leafhoppers, is endemic in Ghana and can take a whole field in a bad outbreak, and the parasitic weed Striga saps yields on tired northern soils; both are managed mainly by planting resistant or tolerant varieties²⁰, which keeps a steady demand for resistant seed and clean-field advice. Further out, maize lethal necrosis is a viral disease that can destroy an entire field. It is established in East and Central Africa but has not been confirmed in Ghana or the rest of West Africa²¹, and Ghana’s breeders at WACCI are already working on resistant lines²². For a seed, diagnostics or surveillance business, the opening is to get ahead of it, positioning resistant varieties and early detection before the disease arrives, not after it has spread.

A drought-stressed maize field with curled, dry leaves under a hot sky

The largest single risk

Drought-tolerant seed, index insurance and irrigation are growing markets.

Purple-flowered Striga parasitic weed growing among stunted maize plants

What it is

Stem borers hollow the stem while the parasitic weed Striga saps the crop on tired northern soils, together causing significant losses in bad cases.

Evidence

Significant loss in bad cases; both managed mainly by tolerant varieties and better agronomy²⁰

Who it hits

Northern uplands on poor, tired soils.

How to manage it, and the opening

Plant tolerant seed and use push-pull and agronomy advice. The opening: tolerant seed and an agronomy advisory service.

🌽 The Opening: turning each threat into a product or service 🌽

01

A scouting and timed-spray service against armyworm. Farmers waste money spraying at the wrong time. A field agent who scouts, identifies the pest and sprays the right product once, at the right moment, sells a service that pays for itself in saved crop.

02

Biopesticide and Bt distribution. Effective, safer products such as neem and Bt formulations work as well as chemicals but are under-supplied in rural markets. Stocking and demonstrating them, and selling the armyworm-tolerant Wobil Moya hybrid, is an agro-dealer opportunity.

03

Aflatoxin-safe grain aggregation. Buy, dry, test and store to a tested low-aflatoxin standard, then sell at a premium to feed mills and institutional buyers that reject contaminated grain. Clean grain is a branded product, not just a safe one.

04

A testing, certification and Aflasafe service. Simple aflatoxin testing at the point of aggregation lets buyers trust a lot, and applying Aflasafe GH02 with hermetic bags sells a trial-backed reduction in aflatoxin as a package. The test, the certificate and the application are all service businesses.

05

Hermetic storage supply. PICS-type bags cost about US$2, cut losses to near zero, and reach fewer than one in five farmers. Stocking, financing and demonstrating them, alongside drying and warehousing, is a straightforward rural business with steady demand.

06

Weather-index insurance, drought seed and small irrigation. As the rains grow less reliable, index insurance and drought-tolerant hybrids move from optional to essential, and affordable irrigation for a dry-season crop is a premium-yield play. Distributing any of them taps a growing, climate-driven market.

🌽 Key takeaways 🌽

01

Every maize threat is also a market: armyworm sells scouting and biopesticides, aflatoxin sells testing and safe storage, drought sells tolerant seed and insurance.

02

Fall armyworm takes 22 to 67 percent of yield, yet many farmers waste about GH¢1,000 on mistimed sprays. Well-timed biopesticides work as well as chemicals.

03

Aflatoxin is the barrier to the best-paying buyers: over 15 percent of maize exceeds the safety limit, and feed mills and institutional buyers reject it. Aflasafe cut the most toxic form by about 84 percent in a Ghanaian trial, and good storage helps keep it low, making clean grain a premium product.

04

About 15 percent of the crop is lost after harvest, and farmers who sell at harvest and rebuy later lose further value to the seasonal price swing. Cheap hermetic bags fix the first; storage and warehouse receipts fix the second.

05

Over 80 percent of Ghana's farming, and almost all maize, is rain-fed, so drought is the master risk. Drought-tolerant seed, index insurance and small irrigation are growing markets.

Written for each reader

🌽 Practitioner intelligence 🌽

Hover any card to pause and lift it.

For students

Risk is where a graduate can start a business with almost no capital. You do not need land to sell a solution to a problem every farmer has. Learn to identify fall armyworm and time a spray, to run a simple aflatoxin test, or to demonstrate a hermetic bag, and you have a service to sell across a whole district. The gap to fill: farmers know they have these problems but not the timed, tested fix. Being the trained person who delivers it is a job and a venture. The downside to avoid is selling a product without teaching the timing, because a mistimed spray or a wet bag fails and destroys your reputation.

For entrepreneurs

Build the fix into a service, not a one-off sale. Your first move is to pick one threat, armyworm, aflatoxin or storage, and offer the complete solution: product plus application plus a guarantee. Secure a supply of the tested input (biopesticide, Aflasafe, PICS bags) and a few demonstration farmers, then scale on word of mouth. The trap: competing on the cheapest chemical, because you win on results, not price. The incentive to use is that clean, safe grain earns a premium from the buyers in Pillar 2.

For investors

The thesis is that risk-mitigation inputs, biopesticides, Aflasafe, hermetic bags, drought seed and index insurance, have been tested in Ghanaian trials and are still little used, so the runway is long. Diligence asks: the effectiveness evidence, the distribution model, and whether the venture sells a product or a stickier service. The risk: adoption is slow because farmers are cash-poor, so pair the product with credit or an off-take that guarantees the farmer a premium for using it.

For ecosystem actors

The highest-return lever is getting tested fixes to more farmers. Fund and measure the last mile for Aflasafe, hermetic storage and drought-tolerant seed, and back weather-index insurance. The measurable outcome is post-harvest loss falling below 15 percent and the share of aflatoxin-safe grain rising. The failure to avoid is running awareness campaigns without making the actual product affordable and available, which teaches farmers the problem but not the solution.

For students

Risk is where a graduate can start a business with almost no capital. You do not need land to sell a solution to a problem every farmer has. Learn to identify fall armyworm and time a spray, to run a simple aflatoxin test, or to demonstrate a hermetic bag, and you have a service to sell across a whole district. The gap to fill: farmers know they have these problems but not the timed, tested fix. Being the trained person who delivers it is a job and a venture. The downside to avoid is selling a product without teaching the timing, because a mistimed spray or a wet bag fails and destroys your reputation.

For entrepreneurs

Build the fix into a service, not a one-off sale. Your first move is to pick one threat, armyworm, aflatoxin or storage, and offer the complete solution: product plus application plus a guarantee. Secure a supply of the tested input (biopesticide, Aflasafe, PICS bags) and a few demonstration farmers, then scale on word of mouth. The trap: competing on the cheapest chemical, because you win on results, not price. The incentive to use is that clean, safe grain earns a premium from the buyers in Pillar 2.

For investors

The thesis is that risk-mitigation inputs, biopesticides, Aflasafe, hermetic bags, drought seed and index insurance, have been tested in Ghanaian trials and are still little used, so the runway is long. Diligence asks: the effectiveness evidence, the distribution model, and whether the venture sells a product or a stickier service. The risk: adoption is slow because farmers are cash-poor, so pair the product with credit or an off-take that guarantees the farmer a premium for using it.

For ecosystem actors

The highest-return lever is getting tested fixes to more farmers. Fund and measure the last mile for Aflasafe, hermetic storage and drought-tolerant seed, and back weather-index insurance. The measurable outcome is post-harvest loss falling below 15 percent and the share of aflatoxin-safe grain rising. The failure to avoid is running awareness campaigns without making the actual product affordable and available, which teaches farmers the problem but not the solution.

Footnotes

Tambo et al. (2023).↑
Koffi et al. (2020).↑
Agboyi et al. (2023).↑
Kondo et al. (2024).↑
Tham-Agyekum et al. (2023).↑
Agbetiameh et al. (2018).↑
Kortei et al. (2021).↑
Nkansah et al. (2024).↑
Nartey et al. (2025).↑
Kaburi et al. (2025).↑
Ministry of Food & Agriculture and International Food Policy Research Institute (2020).↑
African Postharvest Losses Information System (2021).↑
Opoku et al. (2023).↑
Adams et al. (2024).↑
United States Department of Agriculture (2024).↑
United States Department of Agriculture (2026).↑
Fosu-Mensah et al. (2019).↑
Gyamerah et al. (2024).↑
Ghana Agricultural Insurance Pool (n.d.).↑
Mushayi et al. (2025).↑
Boddupalli et al. (2020).↑
West Africa Centre for Crop Improvement (2020).↑